1. Field of the Invention
The present invention relates to a pipe connector for connecting tubular members, for example pipes for use in conveying pressurized fluids, such as steam, gas or oil, for example in oil or gas exploration and production.
2. Description of the Prior Art
The main type of pipe connector presently used for tubings and casings comprises a female member having an internal circumferential surface provided with a thread at each end thereof, and a pair of male members each having an external circumferential surface corresponding to the circumferential surfaces of the female member and provided with a thread for threaded engagement with the female member. To seal the connector against internal pressure, an axially directed end surface on the free end of each male member is brought into abutment with a corresponding surface provided internally in the female member and the end of the respective male member is then compressed against the surface of the female member. The compressive force is obtained by screwing the members together tightly and is usually maintained by providing an interference fit between crest and root surfaces of the threads. The integrity of the seal provided in this way can be substantially reduced by the application of a tensile force to the connector or by inadvertent unscrewing of the members of the connector, for example resulting from a lateral blow to one of the members. The greater the compressed volume of the male members and therefore the greater the angle of relative rotation of the male and female members producing this compression, the greater is the strain energy stored in the seal and the better is the connector able to withstand tangential or axial forces or impulses or negative torque tending to cause unscrewing which would reduce the integrity of the seal.
However, there has not been a pipe connected which meets such a requirement. Most of pipe connectors hitherto used tend to reduce the integrity of the seals substantially when any external force acts them.